Reactor



P. A.. VANCE Aug. 26, 1941.

REACTOR Filed Aug. 6, 1937 Inventor; Paul A Vance,

His ttor'ne9 Patented Aug. 26, 1941 BEACTOB Paul A. Vance, Fort Wayne, Ind., signor to Gen.

eral Electric Company, a corporation of New York Application August 6, 1987, Serial N0. 157,758 l1 Claim.l (Cl. 171242)` My invention relates to inductance coils or reactors and concerns particularly saturable reactors.

It is an object oi my invention to provide an improved saturable reactor having a saturating winding which is free from induction by alternating-current circuits. It is likewise an object to provide a saturable reactor which may be so arranged, when desired, that the alternatingcurrent windings do not tend to neutralize the inductance in each other.

It is also an object o! my invention to provide a construction which is virtually self-supporting and which requires a minimum oi.' material, particularly iron and copper, so as to minimize cost and weight. It is a further object of the invention to utilize a construction in which economy is effected by avoidance of scrap or waste material in the process of construction.

' It is still another object ot my invention to provide a construction in which the reactor core may be operated at high flux density and with relatively low energy loss.

In carrying out my invention in its preferred form, I utilize a pair of strip-wound cores, such as those described in the copending application of John C. Granileld, Serial No. 123,249, led January 30, 193'?, now Pat. 2,160,588, May 30, 1939, and assigned to the same assignee as the present invention, and a winding structure consisting of two altemating-current windings surrounded by a direct-current winding. One of the cores is wound into one of the alternatingcurrent windings and the other core is wound into the other alternating-current winding so that each of the alternating-current windings links one of the cores and the direct-current winding links both cores. The alternating-current windings may be connected either in series or in parallel.

The invention may be understood more readily from the following description when considered application. In the drawing, Fig. 1 is a perspective view of one embodiment of my invention; Fig. 2 representsa modification of the arrangement of Fig. l; Fig. 3 is an elevation ci another modiilcation of the embodiment o! F18. l showing vis e plan view of the arrangement or Fig. a; Fig.

5 is an elevation of still another modiiication of the embodiment of Fig. l with the alternatingcurrent windings transposed to shorten the direct-current winding; and Fig. 6 is a plan view ot the arrangement of Fig. 5. Like reference characters are utilized throughout the drawing to represent like parts.

In the arrangement of Fig. 1, the winding structure consists .oi form-wound alternatingcurrent windings i i and i2 placed in tangency and surrounded by a form-wound direct-current 'winding i3. It will be understood that the windings ii, i2, and I3 include suitable insulating material, such as impregnated paper,.between Tlayers oi turns and 'covering the inside and outside layers oi' turns. 'Pairs of leads il, i5, and il are brought out from the windings il. I 2, and i3, respectively, and may be connected to the desired circuits as in other saturable reactors. 'I'he leads IB are connected to a direct-current circuit and the leads Il and i5 are connected in series or parallel in an alternating-current circuit.

' Strip cores I'I and i8 are wound into the windows i9 and 2li in the windings ii and I2, and so far as possible within practical limits, the cores completely ll the windows Ain the windings and the windings completely illl the cores. In this way, maximum utilization of the material present is obtained and, furthermore, no4 scrap magnetic material results during the process of construction as in the case of cores made up from punched laminations. The cores il and i8 are produced in the manner described in the .above mentioned copending application Serial No. 123,249, being wound preferably, e. g., from high reduction, cold rolled, three per cent silicon steel strip, which has the most favorable magnetic orientation or the grain of 'the strip in the direction o1 rolling, i. e., the length of the strip.

Brieily, such cores are produced in the following manner. A strip of core material ot the proper length having its most favorable magnetic properties in the direction of its length is tightly wound ilatwise upon an arbor or mandrel so that the inside diameter of the spiral coil offstrlp material is of the exact size it is to be in the iinished reactor. The coiled strip is thereupon iastened to prevent the turns from loosening up and is heat-treated as a unit to remove all strains and to set kthe core to size and shape. After heat treatment the strip is simultaneously unwound from the heat-treated coil and appliedl to the winding structure by threading successivel a diiierent arrangement ofthe windings; Fig. 4 55 layers oi' strip through the window in the coil so that the coil surrounds one side of the currentconducting winding and the outside layer of strip remains on the outside. When all of the strip has been transferred to the winding structure. it is collapsed to its original diameter so that the successive layers of strip occupy the same relative position as during heat-treatment and are strain-free to maintain minimum watt losses.

The coils I I, I2, and I3 are so shaped that their sides or legs surrounded by the strip cores I1 and I8 are substantially straight and the windows I8 and 20 have lengths approximately equal to the width o! the magnetic strip, so that the windings can substantially illl the core openings and the cores can substantially fill the windows in the windings.

It will be understood that the reactances oi the alternating-current windings II and I2 are controlled by adjustment o! the current in the direct-current circuit connected to the leads I 8 to effect the necessary degree oi saturation of the cores I1 and IB. The alternating-current windings II and I2 may be connected in either series or parallel but, in either case, are so connected that they tend to produce opposite eilects at any instant with respect to magnetic iiux threading the direct-current winding I3. In this way, reaction between the alternating and direct-current circuits is eliminated. 1n order to avoid reaction between the two alternating-current windings and in cases where unbalancing of the alternating-current fluxes with respect to the direct-current winding may be permissible, in order to permit short-circuiting or shunting of one alternating-current winding for varying its reactance separately without efiect upon the other alternating-current winding, I ordinarily prefer to retain the approximate arrangement oi.' Fig. 1 in which the magnetic circuit ot one alternating-current winding is wholly independent of that of the other since each alternating-current winding has an entirely separate core. However, in cases where it may be desirable, additional alternating iiux carrying capacity may be provided without material eiIect on the area oi the direct-current ilux path by providing a third magnetic core 2| linking both alternating-current windings as illustrated in Fig. 2.

The arrangement of Fig. 1 has the advantage of being virtually self-supporting since the direct current winding I3 binds the alternating-current windings II and I2 together and the strip-wound cores I'I and IB bind the direct-current winding to the alternating-current windings and are in turn supported by the winding structure.

assaoea However, the equivalent electromagnetic eiiects of the arrangement oi.' Fig. 1 may be obtained by arrangements such as those of Figs. 3 and 4 or Figs. 5 and 6. In the arrangement of Figs. 3 and 4, a direct-current winding Il' is placed beside the alternating-current winding II' and I2' instead oi around the alternatingcurrent windings as in Fig. 1. In order to eiIect a saving in the weight and 12R loss in the directcurrent winding, the arrangement of Figs. 5 and 6 may be employed, which, it will be observed, uses the same size core for a given copper crosssection as the other arrangements. In the arrangement of Figs. 5 and 6, current-conducting windings and strip-wound cores alternate with each other, each element linking those on either side to form a structure resembling a chain. A shortened direct-current winding 22 is employed which links each of the cores I'I and I8, and the alternating-current windings II and I2 linking the cores I 'I and I8, respectively, extend outwardly instead o! inwardly as in Fig. l.

I have. herein shown and particularly described certain embodiments of my invention and certain methods of operation embraced therein for the purpose oi explaining its principle and showing its application, but it will be obvious to those skilled in the art that many modifications and variations are possible and I aim, therefore, to cover all such modifications and variations as fall within the scope olf my invention which is deiined in the appended claim.

- What I claim as new and desire to secure by Letters Pat/ent of the United States, is:

A saturable reactor comprising a pair of formwound alternating-current windings having core windows therein and placed tangent, a directcurrent winding surrounding the other two windings, a magnetic core composed oi.' a strip of magnetic material spirally wound ilatwise closely around contiguous sides of said alternating-current windings and partially filling the core windows therein, a magnetic core composed oi' a strip of magnetic material spirally wound iiatwise closely around both one side of said directcurrent winding and the remaining side of one of said alternating-current windings and substantiall;1 filling the remainder of the core win- 4dow therein, and a magnetic core composed of a strip of magnetic material sprally wound fiatwise closely around both the remaining side ot said direct current winding and the remaining side of the other of said alternating current windings and substantially filling the remainder of the core window in said other alternating current winding.

PAUL A. VANCE. 

